Stool



FIG. 1 is a front view of a stool;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a top and front perspective view thereof; and,

FIG. 5 is a bottom and rear perspective view thereof.

Broken lines depict environmental subject matter only and form no part of the claimed design. 

CLAIM The ornamental design for a stool, as shown and described. 